From patchwork Mon Aug 16 14:02:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 12438717 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F978C4320A for ; Mon, 16 Aug 2021 14:03:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 683DA60C40 for ; Mon, 16 Aug 2021 14:03:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236883AbhHPOEI (ORCPT ); Mon, 16 Aug 2021 10:04:08 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:59035 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237424AbhHPODl (ORCPT ); Mon, 16 Aug 2021 10:03:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1629122589; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=wqEhvwu2pAb00bVlZaU9JuLBjS7temg2JRYw9eqMdF4=; b=L2e3Yxf/yL52HqFYN0OLImofbL0HsN3EXhI5/W3ww60kn2iQB128fweXRYUvIgJnzzA2mH BlI+v999xjvlYdmRGjHN0HEMedeMK/z5iGmE9naCPS8diJgrDFz/dnYnKa8qjBL77dfrJ2 m615g+Sxn1A3LEoEzBOxVox2NBXLHTo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-262-VeQbyUkqPNOAxocURXxhKQ-1; Mon, 16 Aug 2021 10:03:03 -0400 X-MC-Unique: VeQbyUkqPNOAxocURXxhKQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D57121008060; Mon, 16 Aug 2021 14:02:59 +0000 (UTC) Received: from avogadro.lan (unknown [10.39.192.155]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7E7855FC25; Mon, 16 Aug 2021 14:02:58 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: stable@vger.kernel.org, Maxim Levitsky Subject: [PATCH 5.12.y] KVM: nSVM: always intercept VMLOAD/VMSAVE when nested (CVE-2021-3656) Date: Mon, 16 Aug 2021 16:02:39 +0200 Message-Id: <20210816140240.11399-11-pbonzini@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Maxim Levitsky [ upstream commit c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc ] If L1 disables VMLOAD/VMSAVE intercepts, and doesn't enable Virtual VMLOAD/VMSAVE (currently not supported for the nested hypervisor), then VMLOAD/VMSAVE must operate on the L1 physical memory, which is only possible by making L0 intercept these instructions. Failure to do so allowed the nested guest to run VMLOAD/VMSAVE unintercepted, and thus read/write portions of the host physical memory. Fixes: 89c8a4984fc9 ("KVM: SVM: Enable Virtual VMLOAD VMSAVE feature") Suggested-by: Paolo Bonzini Signed-off-by: Maxim Levitsky Signed-off-by: Paolo Bonzini --- The above upstream SHA1 is still on its way to Linus arch/x86/kvm/svm/nested.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 4b8635d2296a..8d96c28deadb 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -147,6 +147,9 @@ void recalc_intercepts(struct vcpu_svm *svm) for (i = 0; i < MAX_INTERCEPT; i++) c->intercepts[i] |= g->intercepts[i]; + + vmcb_set_intercept(c, INTERCEPT_VMLOAD); + vmcb_set_intercept(c, INTERCEPT_VMSAVE); } static void copy_vmcb_control_area(struct vmcb_control_area *dst,